The present invention relates to a vertical pouch forming, filling and sealing (VFFS) machine for making pouches and filling them with a liquid content in the range of about 5 to 20 liters.
Traditionally, large plastic film pouches have been fabricated by bag fabricators and shipped to the converters to be filled with a content and then packaged in predetermined numbers in cardboard boxes for shipping to the end users where the bag contents are dispensed, usually through a valve that is secured to a side wall of the bags. This is a labour intensive and costly method as it involves many steps and extra costs in shipping. However, because of the size of these bags, usually capable of holding a liquid content in the range of 5 to 20 liters, it is the only method known to fill these bags as existing equipment is not suitable to fully automate the process.
It is a feature of the present invention to provide a VFFS filler for large pouches as above-described and which substantially overcomes the above-mentioned disadvantages.
According to the above feature, from a broad aspect, the present invention provides a vertical pouch forming, filling and sealing machine for making pouches with a liquid content in the range of about 5 to 20 liters. The machine comprises support means for supporting one or more supply rolls of film material. Guide means is provided to support and guide a film sheet from one of the supply rolls along a feed path. A film feed drive is provided for displacing the film sheet along the feed path and through a pouch former where a section of the film sheet is folded and disposed about a drop tube having a liquid fill tube therein. Vertical sealing means is provided to form a vertical seal along the folded film sheet. Horizontal sealing means is provided to form a bottom seal for a pouch to be filled and a top seal for a filled pouch. Severing means is provided to detach the filled pouch from the pouch to be filled. Support means is provided to support a pouch during the operation cycle of the horizontal sealing means to prevent the weight of the liquid in the filled pouch from tensioning the film in a hot horizontal seal zone of the horizontal sealing means to compensate for loss of surface tension in the film in the hot horizontal seal zone during a hot horizontal sealing cycle. The support means also constrains the pouch being filled to prevent it from ballooning out during the filling cycle. The support means has a discharge gate section to discharge the filled pouch after the horizontal sealing cycle.
According to a further broad aspect of the present invention there is provided a method of vertically forming a pouch from a continuous film sheet, filling the pouch with a liquid content in the range of about 5 to 20 liters and sealing the filled pouch. The method comprises the steps of drawing the film sheet from a supply roll and about guide means along a feed path and through a pouch former. The pouch former is secured at a top end of a drop tube. A section of the film sheet is folded about the bag former to form a folded film tube. The folded film tube is drawn about the drop tube in predetermined length cycles. The drop tube has a liquid fill tube therein. A vertical seal is formed along an overlapped film portion of the film tube and over the drop tube. A horizontal seal is formed by horizontal sealing means to form a bottom horizontal seal for a pouch to be filled with the liquid and simultaneously forming a top horizontal seal for a filled pouch. The filled pouch is severed from the pouch to be filled. The filled pouch is discharged and prior to severing the film pouch, the pouch to be filled is filled with a liquid as the pouch is being drawn in a support means for constraining the pouch to be filled in a cage. The pouch is constrained in the cage throughout the filling cycle to prevent the pouch from ballooning outwardly by the force of the liquid. The support means also supports the pouch during the horizontal sealing cycle to prevent the weight of the liquid in the filled pouch from tensioning the film in the hot horizontal seal zone of the horizontal sealing means whereby to compensate for loss of surface tension of the film in the hot horizontal seal zone during the horizontal sealing cycle.